// extends 继承

class Person {
    constructor(name) {
        this.name = name;
    }

    say() {
        console.log(`hi my name is ${this.name}`);
    }
}

class Student extends Person {
    constructor(name, number) {
        super(name);
        this.number = number;
    }

    hello() {
        super.say();
        console.log(`my school nubmer is ${this.number}`);
    }
}

const s = new Student('jack', 101);
s.hello();
